Vane-type valves are used in a wide variety of applications, for example, as throttle valves for internal combustion engines. In a typical vane valve assembly, a valve body includes a passage, which may be cylindrical although not necessarily, for conveyance of a material such as a gas or liquid. A pivotable shaft is disposed in the valve body and extends across the passage. A vane, also known as a butterfly or throttle, is mounted on the shaft and can partially- to fully-close the passage by rotation of the pivotable shaft to variably control the rate of flow of material through the valve body.
Assembling a vane valve presents well-known logistical problems. For example, in an older prior art valve, the shaft without the vane is mounted into bushings in bores in the body, and the vane is subsequently attached to the shaft. Because the shaft is preferably round in those portions within the bushings, the shaft typically must be either slotted or flatted within the passage to receive the vane. Further, the vane typically is attached to the shaft by screwed fasteners which require anti-rotation devices such as lock washers to guarantee that the vane does not dislodge from the shaft in use, all of which adds to the complexity and expense of a vane valve.
It is known to form the shaft and vane as an integrated unit by molding of plastics, either by forming the shaft itself of a plastic or by overmolding a plastic vane onto a metal shaft. This approach eliminates the interface complexity of fasteners and lock washers between the shaft and the vane, thus reducing manufacturing cost, but at the same time creates new problems in valve assembly. The shaft, now carrying the vane, cannot be inserted directly into the bores in the body as was previously possible. In one known solution, the vane is formed in a slip fit on the shaft, permitting the shaft to be entered into the bores from within the valve passage; however, this approach requires that the vane be secured to the shaft by some means after the shaft is installed.
What is needed in the art is a simple and inexpensive method and apparatus for installing an integrated vane and shaft into a valve body.
It is a principal object of the present invention to simplify the assembly of a vane-type valve having an integrally formed shaft and vane.